In many types of printing, particularly ink-jet printing, there is a need to dry or cure ink placed on a sheet quickly. In a large-scale, high volume ink-jet printing application, particularly where full-color images are placed on a fast-moving continuous web, fusing, drying, curing or other treatment of the web is typically performed by an elaborate fusing, drying, or curing system. (As used herein, all such systems will be generally referred to as “drying.”) These systems very often will apply high temperatures or radiation, such as infrared, to the sheet or web.
With large-scale, high-speed printing apparatus, such as for printing on a web, there may be a need to provide a safety system around the source of the high temperature or other radiation. If, for instance, there is a jam or other anomalous condition in the apparatus, the sheet may accordion within the dryer system, coming into contact with a hot heating or radiation element. It is therefore desirable to enable a covering of the heating or radiation elements under certain conditions. Conversely, there may be reasons for controllably uncovering a heating or radiation element relative to the sheet, such as to control convection heat or other airflow within the apparatus.